1. Field of the Invention
The present invention relates to a substrate processing apparatus that performs a predetermined process of substrates, such as semiconductor wafers, glass substrates for liquid crystal display devices, and glass substrates for PDPs, by using a processing solution.
2. Description of the Background Art
Conventionally, substrate processing apparatuses have been known which perform a predetermined process of cleaning, etching, or the like by supplying a processing solution, such as deionized water, a chemical solution, or the like, to substrates in substrate manufacturing processes. This type of substrate processing apparatuses are generally classified as substrate processing apparatuses of batch processing which perform a predetermined process by immersing a plurality of substrates at a time in a processing solution stored in a processing bath, and substrate processing apparatuses of single wafer processing which perform a predetermined process by discharging a processing solution to the surfaces of substrates that are held one by one by a holding part.
In these substrate processing apparatuses, the process of removing particles adhered on the substrates is carried out at the proper time. Usually, a fluid stream of the processing solution is caused along the surfaces of the substrates, and the action of the fluid stream is used to convey and remove the particles from the surfaces of the substrates. In an alternative, ultrasonic vibration is supplied into the processing solution in order to urge the separation and removal of the particles from the substrates by the shock of the ultrasonic vibration.
In particular, the following technique has been proposed recently. That is, micro bubbles are generated in a processing solution, and high particle adsorbability of the micro bubbles is used to remove particles from the inside of a processing bath. When using micro bubbles, the micro bubbles can be generated in the processing solution by using, for example, a micro bubble generator having a gas-liquid mixing pump, a spin accelerator, and a disperser, or a micro bubble generator having a gas dissolving unit. In order to generate large quantities of micro bubbles in the processing solution, however, it is necessary to use such a large micro bubble generator as described above. This increases the size of the entire substrate processing apparatus.